Chemicals Found in Vegetables Used as Cancer Therapy Aid

SAN DIEGO — A class of cancer-preventing chemicals in cabbage, brussels sprouts, broccoli and cauliflower might be used to protect people against toxic compounds and make radiation treatments and chemotherapy safer, a researcher says.

The chemicals, called dithiolthiones, inhibited cancer formation, reduced radiation damage and protected against harmful toxic materials when fed to rats and mice, said Dr. Ernest Bueding, a pharmacologist at Johns Hopkins University in Baltimore.

He said radiation therapy and chemotherapy to combat cancer sometimes damage non-cancer cells, spurring formation of other tumors after the original cancer has been treated successfully.

Because dithiolthiones seem to protect healthy cells but not cancerous ones, they might be administered in conjunction with radiation or chemotherapy to prevent subsequent cancers, Bueding said.

Laboratory animals given dithiolthiones also were protected against the toxic effects of carbon tetrachloride, a common industrial chemical, and acetaminophen, the active ingredient of painkillers such as Tylenol, he said.

"Such protective effects could provide opportunities for reducing the hazards (to humans) associated with the exposure to, or administration of, these compounds," Bueding added. "Moreover, this type of protection may extend to other as yet untested toxic agents."

The National Academy of Sciences has previously reported scientific evidence indicating that consumption of such vegetables as cabbage, brussels sprouts, broccoli and cauliflower is associated with a reduced incidence of cancer in humans.

The American Cancer Society and National Cancer Institute have recommended people eat more such vegetables--as well as other fruits and vegetables containing fiber--to reduce their cancer risk.

Bueding said his studies with rats and mice show that "the prevention of cancer by vegetable diets could be accounted for, at least in part, by the presence of dithiolthiones in cruciferous vegetables," or vegetables of the mustard family, such as cabbage.

In addition to identifying these chemicals as cancer-preventing agents, Bueding said further research disclosed dithiolthiones enhanced specific defense mechanisms in the animals.

When the rats and mice were given dithiolthiones, their body tissues were found to contain increased levels of glutathione, a compound necessary for proper conversion of food to energy in cells. Glutathione also is involved in many processes that detoxify harmful materials in the body, Bueding said.

Toxic Compounds Inactivated

"Inactivation and subsequent excretion of toxic compounds, including carcinogens, prevents them from combining with vital compounds of the cell, thereby providing protection," he explained.

Bueding concluded, "Better understanding of the biological properties of dithiolthiones could be of value for the protection of man against injury by chemical and physical agents."

Dr. Saul B. Gusberg of New York's Mt. Sinai School of Medicine said Bueding's research "has done a very important, interesting and delicious thing for us" by identifying dithiolthiones as the anti-cancer ingredient in vegetables.

However, he joked that the research may not help increase consumption of the beneficial vegetables because "some people say, 'What's life (like) eating brussels sprouts?' "